Leucine-973 is a Crucial Residue Differentiating Insulin and IGF-1 Receptor Signaling
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ABSTRACT: Insulin and IGF-1 receptors (IR/IGF1R) are highly homologous and share similar signaling systems, but each has a unique physiological role, with IR primarily regulating metabolic homeostasis and IGF1R regulating mitogenic control and growth. Here, we show that replacement of a single amino acid at position 973, just distal to the NPEY motif in the intracellular juxtamembrane region, from leucine, which is highly-conserved in IRs, to phenylalanine, the highly-conserved homologous residue in IGF1Rs, results in decreased IRS-1-PI3K-Akt-mTORC1 signaling and increased of Shc-Gab1-MAPK-cell cycle signaling. As a result, cells expressing L973F-IR exhibit decreased insulin-induced glucose uptake, increased cell growth and impaired receptor internalization. Mice with knockin of the L973F-IR show similar alterations in signaling in vivo, and this leads to decreased insulin sensitivity, a modest increase in growth and decreased weight gain when challenged with high-fat diet. Thus, leucine973 in the juxtamembrane region of the IR acts is a crucial residue differentiating IR signaling from IGF1R signaling.
INSTRUMENT(S): Q Exactive HF
ORGANISM(S): Mus Musculus (mouse)
TISSUE(S): Epithelial Cell
SUBMITTER: Martin Steger
LAB HEAD: Ronald Kahn
PROVIDER: PXD038649 | Pride | 2022-12-21
REPOSITORIES: Pride
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